<html><body><div style="color:#000; background-color:#fff; font-family:verdana, helvetica, sans-serif;font-size:10pt"><div><span>Thanks a ton for the info Paul!</span></div><div><span>Eric<br></span></div><div><br></div> <div style="font-family: verdana,helvetica,sans-serif; font-size: 10pt;"> <div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> <hr size="1"> <b><span style="font-weight: bold;">From:</span></b> Paul & Andrea Mumby <themumbys@gmail.com><br> <b><span style="font-weight: bold;">To:</span></b> Darcy Whyte <darcy@siteware.com> <br><b><span style="font-weight: bold;">Cc:</span></b> eric.schmidt@rogers.com; ModLab <lab@artengine.ca> <br> <b><span style="font-weight: bold;">Sent:</span></b> Wednesday, January 11, 2012 1:53:10 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [Lab] Questions: 1) DIY PCB etching and 2) O-scope in
lab?<br> </font> </div> <br><div id="yiv768964608">Here's my comments:<div><br></div><div>FeCl3 etchant can be messy, but it's not too bad to etch with in the home if your careful with it.</div><div><br></div><div>HCL+H2O2 etchant can be dangerous to mix if your not careful about it (HCL can be nasty to get on the skin, where FeCl3 will just stain it, and irritate it, HCL will cause major chemical burns). Once mixed the etchant isn't that bad though. It is still a stronger acid than FeCl3, and is very adept at dissolving proteins (flesh) so not super ideal to get on your skin, but at least you wouldn't be etching with it at full strength normally. Also mixing with any kind of Oxidizer (which in some cases H2O2 will act as) will gas off pure Chlorine Gas which is nasty stuff too... Even the low concentration hardware store Muriatic Acid you would buy would be strong enough for major chemical burns if not careful.</div>
<div><br></div><div>That said the HCL+H2O2 Etchant is cleaner for the environment, it's renewable, and it etches a fair bit faster than FeCl3, and it's not as sensitive to temperature.</div><div><br></div><div>I'm personally happy with FeCl3 in my etching, I don't heat it, I have a fairly cool basement and I etch at ambient temperature (15C-18C) and it takes me about 30min to etch a 4"x6" single sided PCB using the Toner Transfer method. I use plastic tupperware containers with a nice seal to store the etchant in, I drop the board in, seal it up good, and agitate it by slowly rocking the container back and forth by hand. When done I use a larger plastic tub to rinse the board off (And heavily dilute any waste etchant) before rinsing it down the slop sink in my laundry room. I get a couple dozen boards out of a container of etchant. Then I have to deal with the fun of disposing of it. (Heavily diluting, and neutralizing with diluted sodium
hydroxide).</div>
<div><br></div><div>Ultimately etching at home requires dangerous chemicals no matter which method you use. Care needs to be taken in storage, use and disposal to ensure your safety, and environmental impact.</div><div><br>
</div><div>Another much cleaner and easier option is sending the job out to be done to a fab shop.</div><div><br></div><div>One affordable option is Seeedstudio. They will do boards for a great price, and are good to deal with. Their basic service will do 5cm x 5cm PCBs, 2 layers, with silk screen and solder mask. And it's only like $10 for 10 boards, which is $1 per board. Really it's a fantastic price. 10cm x 10cm is only $25 for 10 boards. And you get the nice professional looking PCBs with holes drilled, solder mask, and silk screen layer on it too...</div>
<div><br></div><div>Hope that helps some.</div><div><br></div><div>- Paul</div><div><br></div><div><br></div><div><div><br></div><div><br><br><div class="yiv768964608gmail_quote">On Wed, Jan 11, 2012 at 12:28 PM, Darcy Whyte <span dir="ltr"><<a rel="nofollow" ymailto="mailto:darcy@siteware.com" target="_blank" href="mailto:darcy@siteware.com">darcy@siteware.com</a>></span> wrote:<br>
<blockquote class="yiv768964608gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div><div><div><div>I've not had boards made by mail yet. What about those boards that just have lots of holes? If the circuit is simple that's another way to do it.</div>
<div><br></div><div>I'm betting someone will come forward with a suggestion of where to get a board made. I don't think it's very expensive.</div>
<div><br></div><div>Another list where people are into circuit boards and stuff is OttawaRobotics.org. </div><div><br></div><div>A metal detector is a great project to get kids into making things (and electronics). </div>
<div><br></div></div></div></div><div class="yiv768964608HOEnZb"><div class="yiv768964608h5"><br>
<br><br><div class="yiv768964608gmail_quote">On Wed, Jan 11, 2012 at 12:22 PM, <span dir="ltr"><<a rel="nofollow" ymailto="mailto:eric.schmidt@rogers.com" target="_blank" href="mailto:eric.schmidt@rogers.com">eric.schmidt@rogers.com</a>></span> wrote:<br><blockquote class="yiv768964608gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div><div style="font-size: 10pt; font-family: verdana,helvetica,sans-serif;"><div><span>Thanks Darcy;</span></div><div><br><span></span></div><div><span>Yes, messy and fraught with the possibility of screwups, but I wanted us to do the "full DIY" process at least once.</span></div>
<div><span><br></span></div><div><span>Who would you suggest for the mail-order route, though? I'm curious about the cost of that option.</span></div><div><span><br></span></div><div><span>cheers,</span></div><div><span>Eric</span></div>
<div><br></div> <div style="font-family: verdana,helvetica,sans-serif; font-size: 10pt;"> <div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"> <font face="Arial"> <hr size="1"> <b><span style="font-weight: bold;">From:</span></b> Darcy Whyte <<a rel="nofollow" ymailto="mailto:darcy@siteware.com" target="_blank" href="mailto:darcy@siteware.com">darcy@siteware.com</a>><br>
<b><span style="font-weight: bold;">To:</span></b> <a rel="nofollow" ymailto="mailto:eric.schmidt@rogers.com" target="_blank" href="mailto:eric.schmidt@rogers.com">eric.schmidt@rogers.com</a> <br> <b><span style="font-weight: bold;">Sent:</span></b> Wednesday, January 11, 2012 12:08:17 PM<br>
<b><span style="font-weight: bold;">Subject:</span></b> Re: [Lab] Questions: 1) DIY PCB etching and 2) O-scope in lab?<br> </font><div><div> <br><div><div>I noticed an scope in the lab<br>
Are you bringing the project to the next modlab?</div>
<div> etching sounds messy<br>
Perhaps mail order can solve that one?</div>
<div>Or perhaps a DNC machine? Not the best method but it might be easier </div>
<div>On Jan 11, 2012 12:01 PM, <<a rel="nofollow" ymailto="mailto:eric.schmidt@rogers.com" target="_blank" href="mailto:eric.schmidt@rogers.com">eric.schmidt@rogers.com</a>> wrote:<br><blockquote style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div><div style="font-size: 10pt; font-family: verdana,helvetica,sans-serif;"><div>So, I've bitten the bullet after lots of lurking on the list, and have initiated our first "dad and kids" electronics project (ok, it'll be vastly "dad with kids looking on")<br>
</div><div>We're going to make this metal detector: <a rel="nofollow" target="_blank" href="http://makeprojects.com/Project/Treasure-Finder/1113/1">http://makeprojects.com/Project/Treasure-Finder/1113/1</a></div><div>
<br></div><div>
I'm just wondering how many of you have done PCB etching using the toner-transfer method.</div><div>After going through a bunch of youtube videos on the etching process, some of them mention the stinkyness/toxicity of the fumes from the acid bath. I bought FeCl3 etchant from Active, but now I'm thinking that maybe HCL+H202 would be better, as described here:</div>
<div><a rel="nofollow">http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/</a><br></div><div><br></div><div>Regardless of etchant, though, in mid-winter, doing it in the garage is probably out of the question due to the cold (or is it?) but I assume I have to ventilate the heck out of whatever space we use.</div>
<div><br></div><div>any guidance on the etching process?</div><div><br></div><div>Next question: for this project, you need to tune the reference coil using either an oscilloscope or a frequency-counting multimeter. Does the Lab have either of these? Cuz I don't...</div>
<div><br></div><div>thanks in advance for any wisdom.<br></div><div><br></div><div>cheers,</div><div>Eric<br></div></div></div><br>_______________________________________________<br>
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